TinyDB - 数据查询处理

TinyDB - 存储多个数据

我们已经讨论了如何使用“insert”查询将数据存储到数据库中。类似地，您可以使用“insert_multiple”查询同时存储多个数据项。以下是 TinyDB 中“insert_multiple”查询的语法：

db.insert_multiple ([
   { key1 : value1, key2 : value2, ..., keyN : valueN},
   { key1 : value1, key2 : value2, ..., keyN : valueN }
])

让我们通过几个例子来演示“insert_multiple”查询的工作方式。我们将使用在前面所有章节中使用过的相同的student数据库。

示例 1

让我们看看如何使用insert_multiple查询在我们的'student'表中插入两条学生记录：

from tinydb import TinyDB, Query
db = TinyDB('student.json')
db.insert_multiple([
   {
      "roll_number":6,
      "st_name":"Siya",
      "mark":240,
      "subject":"NoSQL",
      "address":"pune"
   },
   {
      "roll_number":7,
      "st_name":"Adam",
      "mark":210,
      "subject":"oracle",
      "address":"Keral"
   }
])

它将显示新保存记录的文档 ID：

[6, 7]

让我们检查新记录是否已保存到数据库中？使用all()方法，如下所示：

db.all()

它将显示存储在给定表中的所有记录：

[
   {
      "roll_number":1,
      "st_name":"elen",
      "mark":250,
      "subject":"TinyDB",
      "address":"delhi"
   },
   {
      "roll_number":2,
      "st_name":"Ram",
      "mark":[
         250,
         280
      ],
      "subject":[
         "TinyDB",
         "MySQL"
      ],
      "address":"delhi"
   },
   {
      "roll_number":3,
      "st_name":"kevin",
      "mark":[
         180,
         200
      ],
      "subject":[
         "oracle",
         "sql"
      ],
      "address":"keral"
   },
   {
      "roll_number":4,
      "st_name":"lakan",
      "mark":200,
      "subject":"MySQL",
      "address":"mumbai"
   },
   {
      "roll_number":5,
      "st_name":"karan",
      "mark":275,
      "subject":"TinyDB",
      "address":"benglore"
   },
   {
      "roll_number":6,
      "st_name":"Siya",
      "mark":240,
      "subject":"NoSQL",
      "address":"pune"
   },
   {
      "roll_number":7,
      "st_name":"Adam",
      "mark":210,
      "subject":"oracle",
      "address":"Keral"
   }
]

您可以看到两条新的学生记录已保存到数据库中。

示例 2

让我们看看如何使用insert_multiple和for循环同时将多个值插入到表中。使用以下代码：

db.insert_multiple({'roll_number': 10, 'numbers': r} for r in range(3))

它将返回新保存记录的文档 ID：

[8, 9, 10]

再次，使用all()方法验证新记录是否已保存到数据库中？

db.all()

它将获取存储在给定student表中的所有记录：

[
   {
      "roll_number":1,
      "st_name":"elen",
      "mark":250,
      "subject":"TinyDB",
      "address":"delhi"
   },
   {
      "roll_number":2,
      "st_name":"Ram",
      "mark":[
         250,
         280
      ],
      "subject":[
         "TinyDB",
         "MySQL"
      ],
      "address":"delhi"
   },
   {
      "roll_number":3,
      "st_name":"kevin",
      "mark":[
         180,
         200
      ],
      "subject":[
         "oracle",
         "sql"
      ],
      "address":"keral"
   },
   {
      "roll_number":4,
      "st_name":"lakan",
      "mark":200,
      "subject":"MySQL",
      "address":"mumbai"
   },
   {
      "roll_number":5,
      "st_name":"karan",
      "mark":275,
      "subject":"TinyDB",
      "address":"benglore"
   },
   {
      "roll_number":6,
      "st_name":"Siya",
      "mark":240,
      "subject":"NoSQL",
      "address":"pune"
   },
   {
      "roll_number":7,
      "st_name":"Adam",
      "mark":210,
      "subject":"oracle",
      "address":"Keral"
   },
   {
      "roll_number":10,
      "numbers":0
   },
   {
      "roll_number":10,
      "numbers":1
   },
   {
      "roll_number":10,
      "numbers":2
   }
]

注意最后三行。我们使用了insert_multiple方法和for循环插入了三个新条目。